Oh, 180-day-old Happy Meal, why won’t you rot?

Sally Davies knew this photography project — done on a lark to win a bet with a friend — was going to be a little weird. But 24 hours in, it turned really weird.

Davies, a New York artist and photographer, decided to buy a McDonald’s Happy Meal, set it out on a plate in her East Village apartment, and document its gradual decay (or lack thereof). After just one day, her two food-focused dogs — a Shih Tzu named Suki and a small poodle named Charlie — stopped paying any attention to the plate contents.

“They totally lost interest,” Davies said. “That was just unbelievable to me. But there was no more smell after 24 hours, you know?”

Suki and Charlie exhibited their inexplicable behavior back in April. Today, more than six months later, the Happy Meal burger and fries are still sitting there, forlorn and odorless, on the same plate. And as Davies’ numerous photos reveal, they haven’t changed very much at all.

“The top bun is very dry and a small part snapped off,” Davies said. “The burger shrank as it dried out, but nothing much else.”

It begs the question: Why aren’t these kids’ foods decomposing and turning moldy after months of exposure to the open air?

Why won’t it rot?In a statement shared with TODAYshow.com, McDonald’s stressed that it uses quality ingredients in its menu items.

“McDonald’s hamburger patties in the U.S. are made with 100 percent USDA-inspected beef. They are cooked and prepared with salt, pepper and nothing else — no preservatives — no fillers,” said Todd R. Bacon, McDonald’s senior director of quality systems and supply-chain management.

“Our hamburger buns are made from North American-grown wheat flour,” Bacon continued. “Our world-famous French fries are made from potatoes and cooked in a canola-oil blend. These are the same foods that consumers buy every day in their local grocery stores — bread, meat and potatoes.”

As for the decomposition question raised by Davies’ photos, Bacon cautioned against jumping to conclusions.

“It is not possible to provide a detailed explanation regarding these claims without knowing the conditions in which these food items were kept,” Bacon said. “Bacteria and mold only grow under certain conditions. For example, without sufficient moisture — either in the food itself or the environment in which it is held — bacteria and mold and associated decomposition is unlikely.”

Davies’ photography project has triggered a media firestorm, garnering coverage around the world and ultimately contributing to a conversation about what we — and our kids — eat. Scientists from multiple universities have weighed in on the indestructible nature of the fast foods on Davies’ plate, noting additional factors that could be contributing to their lack of moisture: high fat content, and plenty of salt (a natural preservative).

“Anything that is high in fat will be low in moisture,” Washington State University professor Barry Swanson told Salon.com.

Sean O’Keefe, a professor of food science at Virginia Tech, told Salon.com that it isn’t exactly fair to pick on McDonald’s.

“The ingredients are similar to anything you’d see in processed fast food,” O’Keefe said.

According to the McDonald’s website, a Happy Meal with a hamburger with ketchup and a small order of fries contains 480 calories, 20 grams of fat and 680 milligrams of sodium. Similar meals at other fast-food restaurants contain more sodium, fat and calories.

The tale of the intact 12-year-old burgerDavies certainly isn’t the first person to have a little bit of fun at fast food’s expense. Morgan Spurlock documented McDonald’s French fries stubborn unwillingness to decay in the 2004 film “Super Size Me.” And Davies got the idea for her photography project from a woman she read about online.

That woman — a wellness educator and nutrition consultant named Karen Hanrahan — reportedly bought a McDonald’s burger in 1996 and watched, horrified, as it fail to decompose for more than 12 years. Hanrahan used the intact burger to teach people about the benefits of eating healthful, minimally processed foods.

The account of the 12-year-old burger gave Davies such a jolt that she mentioned it to a friend of hers.

“My friend said that was crazy, and that I should not believe everything I read online,” Davies recalled. “He believed it would mold or rot within two to three days if left out on the counter.”

So, Davies and her friend decided to bet on it. She bought a Happy Meal and brought it home on April 10. Her plan: Photograph the meal daily, send the pictures to her friend and win a bet.

She began posting her Happy Meal photos on Facebook and Flickr — and it soon became clear that this was going to be one tedious photography project. So, she started photographing the burger and fries every week or two instead of daily.

About four months into the project, the world began to notice. Davies has been stunned by the attention received for her little project to entertain her friends and win a bet.

Along the line, some have wondered whether the photos are in fact real. Could it be that this is some kind of a hoax?

“All I can say is that this hamburger has been sitting in my living room for over 180 days,” Davies said. “Go buy your own and take it home and put it on your book shelf and call me in a week. You will see that I didn’t make this up.”

She said she didn’t have McDonald’s in her sights when she started the photography project on a whim. She’s been a vegan since she was 15, but even so, she doesn’t have a beef with a particular restaurant chain.

“I am the least activist person,” Davies said. “I’m not out there telling people what they should eat. ... I’m vegan because I went on a date with a guy when I was 15 and he worked at a slaughterhouse. That was the date: He took me to the slaughterhouse to show me where he worked. From that point on, I’ve never been able to eat meat again.”

Davies is an accomplished artist whose work has been featured on “Sex and the City” and “The Oprah Winfrey Show” and is in the collections of Sarah Jessica Parker, Tim Burton, Johnny Depp, Dan Aykroyd and other celebrities. The recent spotlight on her diet and eating preferences has surprised her as much as the media attention for her Happy Meal photos — although she doesn’t mind talking about nutrition at all.

“Listen, I’m not the little artist taking on Big Meat,” Davies said. “But if there’s enough salt and fat in that thing to turn it into a freaking doorstop, you’ve got to wonder: What’s that doing to your arteries? ...

“I prefer to cook at home and eat organic fresh fruits and vegetables and stay out of the doctor’s office. When I am an old person, my goal is to be healthy and not be on any medication for anything. And so far, my diet is working.”